Presbyopia is a vision disorder associated with aging resulting from the failure of the accommodation mechanism of the eye. The accommodative mechanism is driven principally by parasympathetic innervation of the ciliary smooth muscle. In the non-presbyopic eye, this causes the muscle to slide forward in a unified manner and produces an inward movement of the muscle. The result is a reduction in the diameter of the ciliary muscle collar that instigates a series of events leading to an ability to see near objects clearly.
While it is clear that the capsular elasticity of the lens of the eye, i.e., the ability of the lens capsule to mold the lens, diminishes with age, the precise cause of presbyopia remains the subject of debate.
Presbyopia is most frequently treated by the use of reading glasses, bifocals, and progressive multi-focal contact lenses. However, the inconveniences associated with eyeglasses and contact lenses have prompted investigation into, and the development of, surgical techniques aimed at correcting presbyopia.
One such method is anterior ciliary sclerotomy (“ACS”). ACS is based on the theory that accommodation results primarily from ciliary body contraction, with the resulting forward movement of the lens. Its underlying rationale is based on the observation that the lens constantly grows throughout life, gradually crowding the posterior chamber and eventually preventing full function of the ciliary body/zonular complex. The “crowded” state causes the reduction of lens power change with attempt at accommodation. ACS utilizes a series of symmetrical radial, partial-thickness scleral incisions to attempt to make more room for the ciliary body—which in turn allows more space for the lens—by expanding the globe in the area of the ciliary body. However, this procedure has many potential complications, ranging from infection and hemorrhaging to perforation, which could result in retinal detachment, iris injury or prolapse.
Another proposed method for surgical reversal of presbyopia is based on the theory that presbyopia results when the distance between the ciliary body and the equator of the lens and its capsule becomes less with age as a result of the normal growth of the lens. Thus, under this theory presbyopia is treated by increasing the effective working distance of the ciliary muscle. This is accomplished by implanting a series of scleral expansion bands just below the surface of the sclera and outside the cornea. The bands stretch the sclera so that the diameter of the circle describing the intersection of the plane of the ciliary body with the sclera is slightly increased. See, U.S. Pat. Nos. 5,354,331 and 5,489,299 to Schachar. However, at least one study has called into question the accuracy of the theory on which scleral expansion surgery is premised. See, Mathews, “Scleral Expansion Surgery Does Not Restore Accommodation in Human Presbyopia,” Opthamology, Vol. 106, No. 5, May, 1999, pages 873-877. This study concludes that, if scleral expansion surgery does alleviate presbyopia, an explanation other than the restoration of accommodation needs to be found. Schachar also believes that his scleral expansion bands may have utility in the treatment of primary open-angle glaucoma by restoring the level of force which the ciliary muscle exerts on the trabecular meshwork, thus opening the drainage pores and relieving the intra ocular pressure (IOP).
Regardless of the theory employed, there is a need for correcting presbyopia without the use of eyeglasses or contact lenses through a relatively safe and simple procedure that is easily reversible. There is also a need for treating glaucoma that is safe, effective, and simple.
Accordingly it is the principal object of the present invention to provide a surgical method for the treatment of ophthalmic disorders that can be ameliorated by supporting or reinforcing the scleral.
More specifically, it is an object of the present invention to provide a surgical method for treating presbyopia and/or glaucoma.
It is a further object to provide such a method that has a reduced potential for complications and is easily reversible.
It is a still further object of the invention to provide a clip uniquely suited for use in the treatment of presbyopia and/or glaucoma.